Fix nxFile not able to delete file

The nxFile resource throws an error if you try to use it to delete a file.

Remove-Item: Cannot bind argument to parameter 'Path' because it is null.

The root cause is that $nxFileSystemInfo does not have a property named DestinationPath.

[x] Added an entry to the change log under the Unreleased section of the file CHANGELOG.md. Entry should say what was changed and how that affects users (if applicable), and reference the issue being resolved (if applicable).
[x] Resource documentation added/updated in README.md.
[x] Comment-based help added/updated.
[x] Localization strings added/updated in all localization files as appropriate.
[x] Examples appropriately added/updated.
[x] Unit tests added/updated. See DSC Community Testing Guidelines.
[ ] Integration tests added/updated (where possible). See DSC Community Testing Guidelines.
[x] New/changed code adheres to DSC Community Style Guidelines.

Azure / nxtools